The present invention relates to retroviral protease inhibitors and, more particularly relates to novel compounds and a composition and method for inhibiting retroviral proteases. This invention, in particular, relates to N-heterocyclic moiety containing hydroxyethylamine protease inhibitor compounds, a composition and method for inhibiting retroviral proteases such as human immunodeficiency virus (HIV) protease and for treatment or prophylaxis of a retroviral infection, e.g., an HIV infection. The subject invention also relates to processes for making such compounds as well as to intermediates useful in such processes.